Furnace



(No Model.)

J. KEENAN.

FURNACE. No. 487,675. Patented Dec. 6 1892.

i J1 a @O EI Er I extending upward to form a communication UNITED STATESJAMES KEENAN, OF

PATENT ()FFICE.

CHICAGO, ILLINOIS.

FURNACE.

SPECIFICATION forming part of Letters Patent No. 487,675, dated December6, 1892.

Application filed March 16 1892.

To all whom it may concern.-

Be it known that I, JAMES KEENAN, a citizen of the United States ofAmerica, residing at Chicago, in the county of Cook and State ofIllinois, have invented certain new and useful Improvements in Furnaces,of which the following is a specification.

My invention relatesto certain improvements in furnaces forsteam-boilers, designed to insure as nearly as possible a completecombustion for the double purpose of prevention of smoke and economy offuel.

To such ends it consists in certain combinations of the several portionsof the furnace, whereby, first, the hot gases and vapors as they leavethe fire are shielded from direct contact with the comparatively-coldsurface of the boiler until their combustion is completed; second, anample and unfailing supply of air is introduced at the point where mostneeded, and, third,the furnace is guarded as much as possible against arapid cooling down while a new supply of fuel is introduced.

I shall describe below my preferred construction in which my inventionis fully illustrated, and shall thereafter point out the essentialportions thereof. Said preferred form is shownin the drawings by meansof three figures, of which Figure 1 is a vertical longitudinal sectionof the furnace; Fig. 2, a transverse vertical section in line 2 2 ofFig. 1; and Fig. 3, a similar section in line 3 3 of Fig. 1, the view inboth of the last two figures being from left to right.

The boiler A rests upon the side walls B by means of brackets orsaddle-plates a.

In the furnace O are a grate c and an ash-pit 0'. Above the grate is anarch D, shielding the boiler from a direct contact with the fire andextending backward over a hollow bridge-wall E. Beyond thisbridge-Wallis a combustionchamber F, containing in the rear portionthereof a division-wall or second bridge-wall G, having an arch g in thelower portion thereof. In rear of this division-wall there is acontinuation F of the combustion-chamber with the boiler-fines. Thehollow bridge-wall E is capped by a perforated plate a, preferablyextending over the top and part way Serial No. 125,096. (No model.)

down the rear side thereof, and from the bottom of said plate a fillingH is .made to form an incline downward and backward to .the arch g.WVithin the bridge-wall a pipe 6 extends from side to side of thefurnace, containing a number of perforations and being connected by apipe 6 with the steam-space of the boiler. A stop-cock e is arrangedwithin easy reach of said pipe 6 The interior of the bridge-wall alsoconnects by means of a hole a, provided with a suitable cover, with anair-supply.

The operation is as follows: The hot gases and vapors from the fire uponthe grate rising upward from the same impinge upon the arch D, heatingthe latter to a high temperature. From there they pass backward and aredrawn downward by the draft through the arch g, from which they rise andpass backward through the boilerfiues. In the hot fires that arenecessarily employed under steam-boilers, the gases rising from thecoals contain a large proportion of fuel in an unburned condition. Aslong as these gases are kept at the high temperature at which combustionstarts and suflicient air is supplied, the burning will continue untilthe fuel is entirely consumed. If, however, the gases are cooleddownbeyond the point of ignition, the unburned particles will be carriedonward by the draft and discharged from the chimney in the form ofsmoke.

One of the most common faults in the ordinary steam-boiler furnace isthat the hot gases from the fireimpinge directly upon the boiler itself,which is necessarily of a much lower temperature and which constantlyrapidly cools them down. It should be noticed that in the constructionjust described, the hot gases are prevented from coming directly intocontact with the boiler-shell until they have passed backward throughthe arch g and then upward into the boiler-lines. In the mean time theycan come in contact only with the arch D, the bridge-wall E, the fillingH, and the division-Wall G, all of which parts are heated to a greatdegree and hence assist rather than prevent the combustion. Theirassistance is especially necessary when the doors of the furnace areopen for the purpose of putting in a new supply of fuel. At such a timeimmense quantities of cold air are let in directly above the fire, andwere it not for these heated portions of the furnace, against which airand gases of combustion are carried before they reach the boiler, thelatter would cool them down to a point at which large quantities of sootwould be deposited upon the shell and still greater quantites carriedupward through the chimney.

To insure an ample supply of air, the bridge-wall E is made hollow andconnected with a suitable air-supply, and the perforated plate 6 isplaced upon the top of said wall to discharge the air both upward andrearward in the best possible position and direction to assist in thecombustion of the gases escaping from the fire.

The perforated pipe e, connected with the steam-space of the boiler, isprovided so that steam may be blown into the interior of the bridge-wallnow and then to clear out the perforations in the plate 6.

1 claim as new and desire to secure by Letters Patent In a steam-boilerfurnace, the combination of the arch D, the hollow bridge-wall E, havingthe steam-pipe e, the filling H, and the division-wall G, having anopening in the lower portion thereof, substantially as described.

JAMES KEENAN.

\Vitnesses:

II. BITNER, Cams. 0. SHERVEY.

